CBS Thursday announced the launch of a national sports radio network that will include two stations in Baltimore and looks to seriously challenge ESPN dominance of the sports-talk airwaves.

The CBS action, which includes Cumulus Media, another broadcasting giant, will make for an audience of about 10 million listeners when the network debuts Jan. 2.

CBS Sports Radio will be able to draw on such resources as CBS Sports, CBS News and cbssports.com, making it one of the most impressive sources of sports information in broadcasting right off the bat.

In Baltimore, CBS Sports will air 24/7 on WJZ-AM, while only certain elements of it will be carried on WJZ-FM (105.7 The Fan). Local on-air personalities like Scott Garceau and Steve Davis will not be replaced by national hosts, according to Bob Phillips, senior vice president CBS Radio Baltimore. Both stations are owned by CBS, which also owns WJZ-TV (Channel 13).

"This is a huge move by CBS to bring all the different content together and now to have a network of sports radio stations tied together all across the country," Phillips said Thursday in a phone interiew.

"Having the AM and FM here in Baltimore, the FM will continue to be a locally-focused sports station with local personalities focusing on local teams and local sports talk," Phillips said. "The AM will now move in January to carrying the CBS Sports network."

The WJZ station at 1300 AM now carries ESPN, and the shift that will take place there is representative of the way in which ESPN will be challenged by today's announcement.

While Phillips stressed the importance of having local personalities, it is hard to believe there won't be some cases of on-air hosts not getting renewed as CBS looks for economies of scale throughout the network.

In an unprecedented move that establishes what will be the nation’s most listened to sports radio network across the Top 50 markets, CBS Corporation today announced it has created CBS Sports Radio, a 24-hour, seven-day-a-week lineup of national programming from premier entities CBS RADIO and CBS Sports.

Cumulus Media, the largest pure-play radio broadcaster in the United States, is the network’s exclusive syndicator and sales partner to secure affiliate agreements and ad sales with radio stations nationwide through Cumulus Media Networks. In addition, Cumulus will make CBS Sports Radio programming available on 67 of its owned stations.

At launch, CBS Sports Radio will reach listeners in nine of the nation’s Top 10 markets, with a cumulative audience reach at debut close to 10 million listeners – nearly 90% of them located in Top 50 markets.

“As one of the leading media companies in the world, and a dominant force in sports programming, we look forward to bringing to bear the full resources of CBS and capitalizing on an exciting new growth opportunity for the company,” said Leslie Moonves, President and CEO, CBS Corporation. “CBS Sports and CBS RADIO have been widely recognized for their outstanding contributions to sports broadcasting. This next step in their evolution will serve an ever-expanding audience of sports fans from coast to coast.”

“We are pleased to partner with CBS to deliver the leading entrant into the sports radio market,” said Lew Dickey, Chairman, President and CEO, Cumulus Media. “CBS Sports Radio is an exciting opportunity for us to offer compelling sports content to listeners nationwide, and unique sports marketing opportunities for our advertisers.”

CBS Sports Radio is designed to enhance CBS’s existing sports properties and extend the national reach of the CBS Sports and CBS RADIO brands to additional outlets across the country. Programming will be led by the award-winning team at CBS RADIO, owners and operators of such #1-rated sports stations WFAN-AM in New York, WSCR-AM in Chicago, WIP-FM in Philadelphia, WBZ-FM in Boston and WXYT-FM in Detroit, among others.

“This is a great day for CBS RADIO and sports fans nationwide,” said Dan Mason, President and CEO, CBS RADIO. “For more than two decades we have owned local sports radio and appreciate great talent and programming that resonates with listeners and elicits passionate dialogue and debate. We are bullish our expertise and prior achievements will allow us to successfully complement our existing businesses while expanding into what until now has been a largely unchallenged sector of the radio business.”

“In this era of growing multimedia platforms, the addition of a national radio network to CBS Sports' broadcast, cable and digital properties allows us to extend the storied CBS Sports brand to radio listeners across the country,” said Sean McManus, Chairman, CBS Sports. “We are pleased CBS Sports Radio will allow fans to consume CBS Sports content on a different platform from some of the most recognizable and respected broadcasters in the industry.”

Elements of CBS Sports Radio will include:

24/7 all-sports talk radio lineup to debut on Wednesday, Jan. 2, 2013. Original programs across multiple weekday and weekend time periods will feature expert sports commentary and interviews with major sports figures along with listener calls and fan interaction. All shows will broadcast live with an array of hosts, anchor teams and contributors.

Opportunities for affiliates to regionalize their lineup by choosing from select programs currently featured on CBS RADIO or Cumulus sports stations.

Beginning on Tuesday, Sept. 4, CBS Sports updates can be heard on all network affiliate stations (see attached list). Headlines, breaking news and scores from the day’s major events and stories will be heard hourly.

Contributions from sport-specific experts, as well as a prominent role on the network from CBS Sports, CBS Sports Networks and CBSSports.com’s roster of high-profile personalities delivering analysis, features and special reports.

Online streaming of live network broadcasts.

The following CBS RADIO stations will add various components of CBS Sports Radio programming to their lineup: